Bash布尔表达式及其值分配 [英] Bash boolean expression and its value assignment

问题描述

有没有一种方法可以评估布尔表达式并将其值分配给变量?

Is there a way to to evaluate a boolean expression and assign its value to a variable?

在大多数脚本语言中，都有一种方法可以评估例如

In most of the scripting languages there is way to evaluates e.g

//PHS
$found= $count > 0 ;  //evaluates to a boolean values

我希望以类似的方式在bash中进行评估:

I want similar way to evaluate in bash:

BOOL=[ "$PROCEED" -ne  "y" ] ; 

这无法正常工作，并尝试了其他方法，但无法获得布尔值.有没有办法 不用IF就能做到吗?

This is not working and tried other way but could not get a boolean value. IS there a way to do this WITHOUT using IF ?

推荐答案

您可以这样做:

[ "$PROCEED" = "y" ] ; BOOL=$?

如果您正在使用set -e，则可以改用:

If you're working with set -e, you can use instead:

[ "$PROCEED" = "y" ] && BOOL=0 || BOOL=1

_{BOOL在存在匹配项时设置为零，以像典型的Unix返回码一样工作.看起来有点怪.}

_{BOOL set to zero when there is a match, to act like typical Unix return codes. Looks a bit weird.}

这不会引发错误，并且您确定$BOOL之后将为0或1，无论之前包含什么.

This will not throw errors, and you're sure $BOOL will be either 0 or 1 afterwards, whatever it contained before.

这篇关于Bash布尔表达式及其值分配的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！